Distribute the -1/2 to both x and 12
-1/2(x) = -1/2x
-1/2(12) = -6
12 - (-1/2x) - 6
Simplify: Note, two negatives = one positive
12 + 1/2x - 6
Simplify: combine common numbers together
12 - 6 + 1/2x
6 + 1/2x
1/2x + 6 is your equivalent expression
hope this helps